Electrostatic air cleaner and control means therefor



April 7, 1970 w. H. GOETTL 3,504,482

' ELECTROSTATIC AIR CLEANER AND CONTROLMEANS THEREFOR Filed Jan. 22,1965 2 Sheets-Sheet 1 INVENTOR WILL. M u 0051-11.

April 7, 1970 Filed Jan. 22, 1965 area 0 POT I la A f; J..

w. H. GOETTL ELECTROSTATIC AIR CLEANER AND CONTROL MEANS THEREFOR 2Sheets-Sheet 2 INVENTOR WILLIAM a; 90m n.

United States Patent 3,504,482 ELECTROSTATIC AIR CLEANER AND CONTROLMEANS THEREFOR William H. Goettl, 4627 N. Granite Reef Road, Scottsdale,Ariz. 85251 Filed Jan. 22, 1965, Ser. No. 427,221 Int. Cl. B03c 3/02 US.Cl. 55-139 7 Claims ABSTRACT OF THE DISCLOSURE Au electrostaticprecipitator installed in a building heating system return air ducthaving a flow sensing means to tie-energize the precipitator uponpredetermined decrease in air flow rate in the system. The electrostaticprecipitator having a grounding means to ground the precipitator todissipate residual charges therein as the precipitator is removed fromthe system.

This invention relates to an electrostatic air cleaner and control meanstherefor.

Electrostatic air cleaners are generally used to collect very fineparticulate matter from air in air conditioning systems and are soenergized as to generate ozone at times when a minimum air flowcondition exists relative to such electrostatic air cleaners.

The generation of ozone by one of these units internally of a buildingroom may cause dangerous atmospheric conditions and therefore variousprior art devices have been employed for the purpose of insuring airflow across electrostatic air cleaners to maintain them at a safecondition so that a concentration of ozone is not created in the area ofthe electrostatic air cleaner. Prior art systems have included meanscoupled to blowers and particularly blower motors for the purpose ofde-energizing such electrostatic air cleaners when the blower motors areinoperative.

In such prior art systems a common hazard exists when a belt connectingthe motor and the blower fails and when the motor continues to operate.This condition, of course, causes a minimum air flow condition to occur,namely, one in which the blower does not move any air through the airflow path in which the electrostatic air cleaner is disposed. In thiscondition, the electrostatic air cleaner continues to be energized, itstemperature increases and ozone is created in the area of the cleaner.Thus, the ozone concentration may reach a dangerous condition in abuilding room. The prior art systems have also been expensive since eachelectrostatic air cleaner must include custom installation of theelectrical wiring related to various blowers and motors of existing airconditioning systems. Some of these systems include two blowers or aplurality of blowers for the heating and the refrigeration systems and,accordingly, the coupling of an electrostatic air cleaner to both thesystems alternately to operate in the summer and winter becomes verycomplicated and expensive to install. All of this has been a conditionof prior art installations due to the fact that such prior art systemshave relied upon controlling the electrostatic air cleaner in responseto blower motor operation.

Accordingly, it is an object of the present invention to provide a verysimple electrostatic air cleaner control means wherein an air flowresponsive means in the air flow path relative to the electrostatic aircleaner provides for de-energization of the electrostatic air cleanerwhen air flow reaches a predetermined minimum value.

Another object of the invention is to provide an electrostatic aircleaner and control means wherein an electrostatic air cleaner assemblyis mounted in a frame also carrying an energizing source for theelectrostatic air ice cleaner and also an air flow responsive switchmeans, whereby power supplied to the electrostatic air cleaner may be inthe form of a conventional extension cord having a plug which fits intoa conventional wall outlet, whereby de-energization of the electrostaticair cleaner may automatically take place when a minimum air flowcondition is sensed by the air flow responsive switch means in responseto a minimum air flow relative to the electrostatic air cleaner.

Another object of the invention is to provide a novel means forgrounding the static charge on an electrostatic air cleaner when it ismoved relative to a supporting frame for service.

Another object of the invention is to provide a novel electrostatic aircleaner which may form a return grill for the inlet of an air flowreturn duct of an air conditioning system which has its inletcommunicating withthe interior of a building room.

Another object of the invention is to provide an electrostatic aircleaner which is very economical to produce and install since itrequires no cooperative electrical coupling or wiring relative to airconditioning system blower motors, or the like.

Another object of the invention is to provide a very safe electrostaticair cleaner controlled by an air flow responsive switch responsive toair flow relative to the electrostatic air cleaner and whichelectrostatic air cleaner requires only an electrical connection to aconventional household or commercial power supply.

Further objects and advantages of the invention may be apparent from thefollowing specification, appended claims and accompanying drawings, inwhich:

FIG. 1 is a front elevational view of an electrostatic air cleaner inaccordance with the present invention;

FIG. 2 is a front perspective view of an electrostatic air cleaner inaccordance with the present invention and showing an electrostaticassembly structure pivoted in open position relative to an air flow pathof a frame of the invention which frame is disposed at an air returninlet of an air conditioning system;

FIG. 3 is an enlarged fragmentary sectional view taken from the line 3-3of FIG. 1, showing electrical contacts for conducting energy to theelectrostatic air cleaner of the invention and also for automaticallygrounding the static charge of the assembly during an opening movementof the electrostatic assembly relative to the frame of the invention sothat when the unit is open, the static charge is relieved from the unitto prevent shock to any person who may touch the electrostatic assembly;and

FIG. 4 is a diagrammatic view of the electrical wiring and controlscoupled to an electrostatic air cleaner of the invention andillustrating air flow path means in relation to the electrostatic aircleaner of the invention.

As shown in FIG. 1 of the drawings, the electrostatic air cleaner of theinvention is provided with a frame 10 having an opening 12 in which anelectrostatic air cleaning assembly 14 is movably mounted by means of ahorizontally disposed hinge 16 at the lower portion of the assembly 14.

A housing portion 18 of the frame 10 encloses the conventionalelectrostatic energizing circuitry of the invention for energizing theelectrostatic assembly 14, all as will be hereinafter described.

A power conductor cord 20 is provided with male conductor prongs 22adapted to be plugged into a conventional household power outlet andthis cord 20- is adapted to conduct electrical energy to theelectrostatic charging circuitry contained in the housing 18, as will behereinafter described in detail.

As shown in FIG. 2 of the drawings, the assembly 14 is pivoted about theaxis of the hinge 16 into open position relative to the opening 12 inthe frame 10, said opening 12 forming a part of an air flow pathaccording to the present invention.

The assembly 14 may be moved to the open position, as shown in FIG. 2,substantially out of the air flow path for the purpose of removing theassembly 14 and cleaning it periodically.

The assembly is provided with a latch 22 engageable with a complementallatch 24 for holding the assembly 14 in closed position, as shown inFIG. 1, relative to the opening 12 and in an air flow path for thepurpose of filtering air which may pass in the air flow path and whichflow may be induced by a conventional blower 24, as shown in FIG. 2,which blower may cause air flow in the direction of arrows A, as shownin FIG. 4 of the drawings,

With specific reference to FIG. 4, it will be seen that the housing 18contains a conventional electrostatic energizing circuit 26 suppliedpower through the cord 20, as hereinbefore described. The electrostaticcharging circuit 26 is provided with a power interrupting switch 28which is normally closed when the assembly .14 is in closed position, asshown in FIG. 1, and open when the assembly 14 is in the open position,shown in FIG. 2, so that power coupled to the conductor cord 20 does notflow into the circuitry 26 when the assembly 14 is in open position, aswill be hereinafter described.

The assembly 14 is provided with a conventional ionizer 30 and aconventional collector 32, the collector 32 being coupled to a movablecontact 34 and the ionizer 30 being coupled to a conventional movablecontact 36, these being shown in FIG. 3 of the drawings, and carried onan insulating plate 38 of the assembly 14. These contacts 34 and 36 areengageable with complemental contacts 38 and 40 when the assembly 14 isin the closed position, as shown in FIG. 1, and as shown in FIG. 3 andin FIG. 2, the contacts 34 and 36 are disconnected from the contacts 38and 40, respectively, when the assembly '14 is in the open position.

A grounding contact 42 is connected to ground and is laterally spacedrelative to the contacts 34 and 36 and 38 and 40, respectively, when theassembly 14 is in closed position so that when it is moved toward openposition, contacts 44 and 46 coupled to the collector and ionizer andcarried by the plate 38 brush the contact 42 and {thereby relieve thestatic charge from the assembly 14 before it reaches a full openposition, as shown in FIG. 2. This grounding contact occurs when thecontacts 34 and 36 and the contacts 44 and 46 are in a position, asindicated at B in FIG. 3 of the drawings.

It will be seen that the contacts 38 and 40 are stationarily mounted inan insulating plate structure 50 carried by the housing 18 in one sideof the opening 12 of the flame and that the grounding contact 42 is alsocarried on this insulating plate 50. With reference to FIGS. 2 and 3 ofthe drawings, the disposition and operationof the foregoing contacts mayreadily be discerned.

Coupled in series with the switch 28 is a pair of contacts 52 and 54which when connected in closed circuit with the switch 28 conduct powerto the electrostatic energizing circuit 26. Thus, when the switch 28 andthe contacts 52 and 54 are coupled in closed position, electrical energymay be transmitted through the conductor cord 20 to energize theelectrostatic energizing circuit 26.

A bridge contact 56 is maintained in normally open position relative tothe contacts 52 and 54 and is coupled to one end 58 of a lever 60 havingan aerodynamic air flow sensing plate 62 coupled thereto. The lever 60is pivoted at 64 and held against a stop 66 by means of a compressionspring 68. When suflicient air flow, more than a minimum amount, ispassing, as indicated by arrows A through the flow path of theinvention, aerodynamic air flow impinges on the air responsive member 62which is thus moved in the same direction as the arrows A causing thebridge contact 56 to close against .4 the contacts 52 and 54 and couplethe same to complete a circuit to the electrostatic energizing circuit26 and to thereby complete a circuit to the assembly 14 when in closedposition, as shown in FIG. 1 of the drawings.

Whenever air flow in the direction of the arrows A stops or reaches apredetermined minimum condition, insufficient force on the air flowsensing member 62 exists and such force is overcome by the spring 68which forces the lever '60 toward the stop 66 and opens the bridgecontact 56 with respect to the contacts 52 and 54, thereby de-energizingthe electrostatic energizing circuit 26 so that continued operation ofthe electrostatic air cleaning assembly 44 may be interrupted until airflow is again resumed in a sufficient amount to again close the contact56 relative to the contacts 52 and 54.

It will be understood that the switch composed of the elements 52, 54and 56 is disclosed only by way of illustration and may actually be aconventional microswitch or any other suitable snap action switch orthis air flow responsive means may be any suitable switch such as apitot tube responsive switch or an air pressure differential switch. Anyequivalent means for operating an electrical switch in response to airflow may be used in accordance with the scope of the present inventionand such air flow responsive means may be sensitive to air flow relativeto the assembly .14 for de-energizing or shutting off power to theelectrostatic energizing circuitry 26.

It will be appreciated by those skilled in the art that this air flowresponsive means may be disposed either upstream or downstream relativeto the assembly 14. However, when the invention is used as an air returnduct inlet grill, the air flow responsive means may be downstreamrelative to the assembly 14.

It will be understood by those skilled in the art that the entireinstallation of the invention may include no more labor than thatrequired to place the frame 10 in position at the inlet of an air returnduct and the plugging in of the prongs 22 of the cord 20 into aconventional volt power supply.

In FIG. 4, an inlet 70 of an air flow return duct 72 receives air fromthe assembly 14, the air passing through ionizer and to the collector inthe conventional manner, whereby material is collected on the collectorbefore the air passes into the inlet '70.

It will be understood that an air flow path in accordance with thepresent invention may include a duct 74 as indicated by broken lines inFIG. 4 of the drawings which communicates with the inlet side of theassembly 14.

I claim:

1. In an electrostatic air cleaner the combination of: first meansforming an air flow path;-an electrostatic air cleaning assembly in saidpath; second means disposed electrostatically to energize said aircleaning assembly; and third means responsive to air flow relative tosaid assembly, said third means disposed to de-energize said secondmeans to thereby de-energize sa d assembly when air flow relative tosaid assembly is substantially reduced said third means comprising amovably mounted aerodynamic flow sensing plate, said plate disposed insaid air flow path and in spaced relation to the downstream side of saidair cleaning assembly, said plate having opposite sides disposed at anangle to the air flow direction from said air cleaning assembly, saidplate having one of said sides adapted to be impinged upon byaerodynamic air flow; and resilient means tending to move said plate inopposition to force of air flow impinging on said plate; and a switchdisposed to be operated by movement of said plate.

2. In an electrostatic air cleaner the combination of: a first meansforming an air flow path; an electrostatic air cleaner in said path; apower source for energizing said electrostatic air cleaner; an air flowresponsive means disposed to be responsive to air flow passing throughsaid path and relative to said electrostatic air cleaner; said air fiowresponsive means disposed to conduct power from said power source to.said electrostatic air cleaner and operable to disconnect and interruptthe flow of power from said power source to said electrostatic aircleaner when a substantially reduced air flow condition exists in saidpath relative to said electrostatic air cleaner, said air flowresponsive means comprising a movably mounted aerodynamic flow sensingplate, said plate disposed in said air flow path, and in spaced relationto the downstream side of said air cleaning assembly, said plate havingopposite sides disposed at an angle to the air flow direction from saidair cleaning assembly, said plate having one of said sides adapted to beimpinged upon by aerodynamic air flow; resilient means tending to movesaid plate in opposition to force of air flow impinging on said plate;and a switch disposed to be operated by movement of said plate.

3. In an electrostatic air cleaner the combination of: first meansforming an air flow path; an electrostatic air cleaning assembly in saidpath; second means disposed electrostatically to energize said aircleaning assembly; and third means responsive to air flow relative tosaid assembly, said third means disposed to de-energize said secondmeans to thereby de-energize said assembly when air flow relative tosaid assembly is substantially reduced said third means comprising amovably mounted aerodynamic -flow sensing plate, said plate disposed insaid air flow path and in spaced relation to the downstream side of saidair cleaning assembly, said plate having op posite sides disposed at anangle to the air fiow direction from said air cleaning assembly, saidplate having one of said sides adapted to be impinged upon byaerodynamic air flow; and resilient means tending to move said plate inopposition to force of air flow impinging on said plate; and a switchdisposed to be operated by movement of said plate; a common frame forsaid assembly and said second means; said second means stationarilymounted in said frame; said assembly movably mounted in said frame andnormally held in said air flow path by said frame.

4. In an electrostatic air cleaner the combination of: first meansforming an air flow path; an electrostatic air cleaning assembly in saidpath; second means disposed electrostatically to energize said aircleaning assembly; and third means responsive to air flow relative tosaid assembly, said third means disposed to de-energize said secondmeans to thereby de-energize said assembly when air flow relative tosaid assembly is substantially reduced said third means comprising amovably mounted aerodynamic flow sensing plate, said plate disposed insaid air flow path andin spaced relation to the downstream side of saidair cleaning assembly, said plate having opposite sides disposed at anangle to the air flow direction from said air cleaning assembly, saidplate having one of said sides adapted to be impinged upon byaerodynamic air flow; and resilient means tending to move said plate inopposition to force of air flow impinging on said plate; and a switchdisposed to be operated by movement of said plate; a common frame forsaid assembly and said second means; said second means stationarilymounted in said frame; said assembly movably mounted in said frame andnormally held in said air flow path by said frame; complemental contactscarried by said frame and said assembly, respectively, for energizingsaid electrostatic air cleaning assembly when said assembly is held insaid air fiow path by said frame; respective contacts on said assemblyand said frame disconnected when said assembly is moved substantiallyout of said air flow path and rela tive to said frame.

5. In an electrostatic air cleaner the combination of: first meansforming an air flow path; an electrostatic air cleaning assembly in saidpath; second means disposed electrostatically to energize said aircleaning assembly; and third means responsive to air flow relative tosaid assembly, said third means disposed to de-energize said secondmeans to thereby de-energize said assembly when air flow relative tosaid assembly is substantially reduced; said third means comprising amovably mounted aerodynamic flow sensing plate, said plate disposed insaid air flow path and in spaced relation to the downstream side of saidair cleaning assembly, said plate having opposite sides disposed at anangle to the air flow direction from said air cleaning assembly, saidplate having one of said sides adapted to be impinged upon byaerodynamic air flow, and resilient means tending to move said plate inopposition to force of air flow impinging on said plate; and a switchdisposed to be operated by movement of said plate; a common frame forsaid assembly and said second means; said second means stationarilymounted in said frame; said assembly movably mounted in said frame andnormally held in a first position in said air flow path by said frame;electrical contact means carried by said frame and said assembly,respectively, for energizing said electrostatic air cleaning assemblywhen said assembly is held in said air flow path by said frame; saidelectrical contact means on said assembly and said frame beingdisconnected when said assembly is moved in a direction to a secondposition substantially out of said air flow path and relative to saidframe; a first grounding contact means carried by said frame and acomplemental grounding contact means carried by said assembly, saidfirst grounding contact means slightly spaced from said electricalcontact means so that movement of said assembly relative to said framein said direction first causes disconnection of said energizingelectrical contact means and then causes engagement of said complementalgrounding contact with said first grounding contact means on said framefor grounding said electrostatic air cleaner assembly and therebydissipating the static charge thereon.

6. In an electrostatic air cleaner the combination of: first meansforming an air flow path; an electrostatic air cleaning'assembly in saidpath; second means disposed electrostatically to energize said aircleaning assembly; and third means responsive to air flow relative tosaid assembly, said third means disposed to de-energize said secondmeans to thereby 'de-energize said assembly when air flow relative tosaid assembly is substantially reduced; said third means comprising amovably mounted aerodynamic flow sensing plate, said plate disposed insaid air flow path and in spaced relation to the downstream side of saidair cleaning assembly, said plate having opposite sides disposed at anangle to the air flow direction from said air cleaning assembly, saidplate having one of said sides adapted to be impinged upon byaerodynamic air flow; and resilient means tending to move said plate inopposition to force of air flow impinging on said plate; and a switchdisposed to be operated by movement of said plate; said first meansbeing an air return duct having an air inlet disposed to receive airfrom the inerior of a room, said electrostatic air cleaning assemblybeing disposed at said duct inlet and forming an air return grill.

7. In an electrostatic air cleaner the combination of: a first meansforming an air flow path; an electrostatic air cleaner in said path; apower source for energizing said electrostatic air cleaner; an air flowresponsive means disposed to be responsive to air flow passing throughsaid path and relative to said electrostatic air cleaner; said air flowresponsive means disposed to conduct power from said power source tosaid electrostatic air cleaner and operable to disconnect and interruptthe flow of power from said power source to said electrostatic aircleaner when a substantially reduced air flow condition exists in saidpath relative to said electrostatic air cleaner; said air flowresponsive means comprising a movably mounted aerodynamic flow sensingplate, said plate disposed in said air flow path; and in spaced relationto the downstream side of said air cleaning assembly, said plate havingopposite sides disposed at angle to the air flow direction from said aircleaning assembly, said plate having one of said sides adapted to beimpinged upon by aerodynamic air flow; resilient means tending to movesaid plate in opposition to force of air flow impinging on said plate;and a switch disposed to be operated by movement of said plate; a commonframe for said assembly and said power source; said power sourcestationarily mounted in said frame; said assem'bly movably mounted insaid frame and held in said air flow path by said frame; said firstmeans being a return air duct having an inlet communicating with theinterior of a building room; said frame and said electrostatic aircleaner being disposed at said inlet of said duct and forming a returnair grill assembly, whereby air flows through said electrostatic aircleaner and into the inlet of said air return duct.

References Cited UNITED STATES PATENTS 1,947,447 2/ 1934 Br-assert et a155-106 X 2,756,839 7/1956 Roberts 55-"106 X 3,188,784 6/=1965 Nodolf55-139 X 3,191,362 6/1965 Bourgeois 55-139 X Koble 55-139 X Gilbertson55-139 Geisenhoner ZOO-81.9 X Mather 20081.9 X Gamille 20081.9 LeifheitZOO-81.9 X Clark 55-210 X 'Pegg 55-105 Coolidge et al. 55-139 Kmiecik eta1. 20081.9

FOREIGN PATENTS 5/1926 France.

HARRY B. THORNTON, Primary Examiner D. E. TALBERT, IR., AssistantExaminer US. Cl. X.R.

